Field of Endeavor
The present invention relates to energy research, and more particularly to indirect-drive for laser-driven energy research utilizing laser beams.
State of Technology
In inertial confinement fusion (ICF), a driver—i.e., a laser, heavy-ion beam or a pulse power system—delivers an intense energy pulse to a target containing around a milligram of deuterium-tritium (DT) fusion fuel in the form of a hollow shell. The fuel shell is rapidly compressed to high densities and temperatures sufficient for thermonuclear fusion to commence. The goal of present ICF research is to obtain ignition and fusion energy gain from a DT target. The gain of an ICF target is defined as the ratio of the fusion energy produced to the driver energy incident on the target and is a key parameter in determining economic viability of future inertial fusion energy power plants. The article, Laser lab shifts focus to warheads, in Nature, Vol. 491, Nov. 8, 2012 includes the statement: “The NNSA is planning to emphasize experiments that mimic conditions inside nuclear weapons, generating data to validate the computer codes used to check that the nation's war heads remain viable essential work, given the voluntary moratorium on underground testing that began in 1992.”
The National Ignition Facility (NIF) is presently seeking to demonstrate energy research in the laboratory for the first time by means of indirect-drive. The laser energy is first converted to x-rays in a hohlraum surrounding the fuel capsule and the x-rays then perform the ablatively-driven compression of the capsule. Direct-drive is an alternative method of imploding ICF targets where the laser beams impinge directly on the capsule surface and directly cause ablation compression. In both cases, ignition is initiated by the PdV work of the high-velocity converging shell stagnating on a central hotspot. The article, The National Ignition Facility: Transition to a User Facility, by E. I. Moses, J. Atherton, L. Lagin, D. Larson, C. Keane, B. MacGowan, R. Patterson, M. Spaeth, B. Van Wonterghem, P. Wegner and R. Kauffman, in Journal of Physics: Conference Series, Volume 688, conference 1, in the abstract includes the statement: “The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) has been operational since Mar. 2009 and has been transitioning to a user facility supporting ignition science, high energy density science (HEDS), national security applications, and fundamental science.”